The overall goal of the project is increased understanding of the influence that drug courts have in motivating treatment retention and post-treatment success when they divert or sentence offenders to outpatient substance abuse treatment. The specific aims are: (1) assessment of 12-month and 24-month post-treatment outcomes for drug court offenders sent to outpatient substance abuse treatment, by examining multiple outcome indicators for diverted and sentenced drug court offenders as well as comparable volunteer treatment clients; (2) examination of the impact of drug court sentencing on retention in outpatient substance abuse treatment; and (3) analysis of variations in treatment treatment motivations, program retention, and post-treatment outcomes for drug court offenders sent to outpatient substance abuse treatment, through hypothesis testing and exploratory study of how those variations are related to addiction careers, treatment careers, and concurrent life problems. In a proposed 5-year study, the project will interview 720 adult offenders sent to outpatient substance abuse treatment by the Delaware Drug Court in Wilmington (New Castle County): 180 offenders referred to each of three programs: diversion to drug education, diversion to outpatient therapy, and sentencing to intensive outpatient treatment. A fourth sample will be 180 volunteer clients with similar drug and crime backgrounds who are also in intensive outpatient treatment at the same treatment agency. Treatment program data will be used to indicate retention, treatment motivation at entry, and substance use before treatment. Treatment outcome indicators for 12 and 24 months after leaving treatment will be official arrest data, urine tests for drug use, and self-reported substance use, crime, employment, family relationships, and health. Analysis will include both hypothesis testing and exploratory analysis, combining outcome assessment of outpatient programs for drug court offenders with specification, testing, and exploration of a theory about how treatment effects are modified by addiction career stages and consequent life problems.